Case comprising a rigid face and a flexible face able to be closed and maintained in the closed state

ABSTRACT

The invention concerns a case comprising a sheet of flexible thin material and a sheet of rigid thick material, the said case comprising: 
         a body ( 36 ) comprising lateral panels ( 5, 6, 7, 9 ) including front ( 5 ) and rear ( 6 ) panels,    an opening ( 34 ), some edges of which carry a lateral lug ( 24, 25 ) comprising a rigid step ( 28, 29 ),    a closure lug comprising an opening/closing panel ( 14 ) with respect to which an entering lug ( 16 ) is foldable at right angles along a folding line ( 17 ), the said folding line comprising removals of material ( 18 ) in which the rigid steps ( 28, 29 ) are inserted when the closure lug is folded over the opening ( 34 ) so as to obtain, because of the rigidity of the thickness of the sheet of rigid thick material, a snapping of the rigid steps ( 28, 29 ) into the removals of material ( 18 ). The invention also concerns a blank for producing such a case as well as a method of producing such a blank.

The invention concerns a case produced by folding a complex comprising a sheet of thin flexible material and a sheet of thick rigid material, a blank intended for producing such a case, and a method of producing such a blank.

There are known, from the document WO 02/00424, packages obtained after folding a sheet consisting of a stack of a layer of flexible material and a rigid layer. To enable it to be folded, the sheet comprises a groove produced in the rigid layer and whose height is equal to the thickness of the rigid layer.

However, manufacturers have not envisaged producing packages comprising closure lugs for obtaining closed volumes. Embodiments of the “matchbox” type have been envisaged, that is to say with a container inserted in a package of the type described above. However, such designs in several pieces are not practical, in particular in the case of the loss of one of the pieces, which makes the package unusable.

The document U.S. Pat. No. 5,065,935 describes a box covered with a packaging paper comprising lateral panels folded over one opening of the box and held by slots inserted in one another.

This type of closure is complex to produce for a package comprising a rigid layer and does not make it possible to keep it firmly closed.

There is also known from the document EP-A-0 709 293 a box comprising a closure panel. A tongue separated from the panel by a folding line comprises openings through which hooks provided on foldable lugs pass when the box is closed.

However, this type of closure, requiring the deformation of the hooks to open the box, is not suitable for a package comprising a rigid layer as it might damage the package.

The invention aims to permit the production of a package comprising a layer of flexible material and a rigid layer able to be closed and maintained firmly in the closed state using the rigidity of the rigid layer.

To this end, and according to a first aspect, the invention concerns a case produced by folding a complex, the said complex comprising a sheet of flexible thin material such as cardboard or plastics material with which there is associated a sheet of rigid thick material such as wood or metal, the said case comprising:

-   -   a body comprising lateral panels, including at least one front         panel and one rear panel,     -   at least one first opening defined by the said lateral panels,         some of the edges of the said opening each carrying a lateral         lug folded at right angles with respect to a lateral panel of         the case along a folding line, the said lateral lugs comprising         a rigid step close to the said folding line and projecting         towards the front panel of the case,         the said case also comprising at least one lug closing the         opening at one of the ends of the body, the said closure lug         comprising an opening/closing panel articulated on the rear         panel along a folding line, the said opening/closing panel         comprising, at its end opposite to the folding line, an entering         lug foldable at right angles with respect to the said         opening/closing panel along a folding line substantially         parallel to the folding line, the folding line comprising in its         end parts a removal of material through each of the sheets in         the complex, the rigid steps on the lateral panels being         inserted in the removals of material when the closure lug is         folded over the opening so as to obtain, because of the rigidity         and thickness of the sheet of rigid thick material, a snapping         of the rigid steps into the removals of material in order to         lock the said closure lug in the position of closure of the         case.

According to a second aspect, the invention concerns a blank intended for producing a case as described above, this blank being produced from a complex comprising a sheet of flexible thin material such as cardboard or plastics material with which there is associated a sheet of rigid thick material such as wood or metal, the said blank comprising:

-   -   lateral panels, including at least one front panel and one rear         panel, separated by folding lines and defining the body of the         case by folding,     -   lateral lugs adjacent to some of the lateral panels and         articulated on these by folding lines,     -   a gluing lug adjacent to the front panel and articulated on this         by a folding line substantially parallel to the folding line         separating the lateral panels,         the said blank also comprising an opening/closing panel adjacent         to the rear panel and articulated on the said rear panel by a         folding line, the said opening/closing panel comprising, at its         end opposite to the folding line, an entering lug, the said lug         being articulated on the opening/closing panel by a folding line         substantially parallel to the folding line, the folding line         comprising, in its end parts, a removal of material, the folding         lines being produced by cropping the sheet of rigid material in         the complex.

According to a third aspect, the invention concerns a method of producing a blank as described above, the said method comprising the following steps:

-   -   producing a complex by associating a sheet of flexible thin         material such as cardboard or plastics material and a sheet of         rigid thick material such as wood or metal;     -   cropping the complex so as to form the lateral panels, the         closure lug, the gluing lug and the lateral lugs;     -   producing the folding lines by cropping the sheet of rigid         material only;     -   producing a cut in the sheet of rigid material close to the         removals of material, the said cut extending partially over the         opening/closing panel and over the entering lug;     -   producing removals of material by complete cutting of the         complex.

Other objects and advantages of the invention will emerge during the following description given with reference to the accompanying drawings, in which:

FIG. 1 is a plan view of the internal face of a blank according to one embodiment of the invention;

FIG. 2 is a perspective view of a case with its closure lug open, issuing from the making up of the blank according to FIG. 1.

In relation to FIG. 1, a blank 1 is described produced from a complex comprising a sheet of flexible thin material, such as cardboard or plastics material, and a sheet of rigid thick material, such as wood or metal. Flexible thin material means a sheet produced from a material whose nature and thickness make it possible to deform the sheet. Sheet of rigid thick material means a sheet produced from a material whose nature and thickness limit the deformation of the sheet. In particular examples, the thickness of the sheet of flexible material is around a few tens of millimetres and that of the sheet of rigid material is around twice that of the sheet of flexible material.

The internal face 3 of the blank 1 is defined as being the face of the blank which will be situated inside the case 2 when the blank is made up, the external face 4 forming the visible face of the case 2 when the latter is formed.

According to the invention, the sheet of flexible thin material forms the internal face 3 of the blank 1 and the sheet of rigid material forms the external face 4. There is thus conferred on the case 2 an external appearance with a particular aesthetic appeal according to the material chosen for the sheet of rigid material. It is also possible to print various bits of information on the external face 4, for example a logo or the like.

The blank 1 comprises lateral panels, including at least one front panel 5 and one rear panel 6.

According to the embodiment depicted, a first lateral panel 7 is articulated on the rear panel 6 by a folding line 8. On the side opposite to this folding line 8, a second lateral panel 9 is articulated on the rear panel 6 by a folding line 10. On the side opposite to this folding line 10, the second lateral panel 9 is articulated on the front panel 5 by a folding line 11.

The set of lateral panels 5, 6, 7 and 9 define the body 36 of the case with a cylindrical shape overall, for example substantially parallelepipedal, when the blank 1 is made up. According to other embodiments which are not shown, it is possible to envisage interposing additional lateral panels between the front 5 and rear 6 panels in order to produce cases with different shapes. Moreover, it is possible to provide for at least one lateral panel 5, 6, 7 and/or 9 to comprise an opening produced by a cut in the complex.

The lateral panels are substantially polygonal, for example rectangular, and the folding lines separating the lateral panels are substantially parallel to each other. It is however possible to provide for the panels to have a trapezoidal shape so as to form a case having an inclined opening.

On the side opposite to the folding line 11, a gluing lug 12 is articulated on the front panel 5 along a folding line 13 substantially parallel to the folding lines 8, 10 and 11.

An opening/closing panel 14 is adjacent to the rear panel 6 and articulated on this along a folding line 15 substantially perpendicular to the folding lines separating the lateral panels. The opening/closing panel 14 has a substantially rectangular shape where the length of the large side corresponds substantially to the length of the small sides of the lateral panels 7 and 9.

An entering lug 16 is articulated on the opening/closing panel 14 at its end opposite to the folding line 15. The entering lug 16 can be folded at right angles with respect to the opening/closing panel 14 along a folding line 17 substantially parallel to the folding line 15. The assembly consisting of opening/closing panel 14 and entering lug 16 form a closure lug intended to close the case 2 when the blank 1 is made up.

To make it possible to lock the closure lug without damaging the case, the folding line 17 comprises, at each of its end parts, a removal of material 18. These removals of material 18 consist of complete cuts of the complex comprising the sheet of flexible material and the sheet of rigid material. The cuts being produced through each of the sheets of the complex, the edges of the removals of material 18 have a certain rigidity and a certain thickness. They extend along the folding line 17 towards the centre of the closure lug, having dimensions which are small compared with the length of the folding line 17.

Close to the removals of material 18, the folding line 17 comprises a cut 19 produced solely in the sheet of rigid material. The cut 19 is substantially perpendicular to the folding line 17 and extends partially over the opening/closing panel 14 on the one hand and over the entering lug 16 on the other hand. The cut 19 marks the end of the removal of material 18. The cut 19 also comprises, on the side of the opening of the closing panel, a wing 20. This wing 20, produced in the sheet of rigid material, is intended to form a projection substantially perpendicular to the opening/closing panel 14 when the entering lug 16 is folded at right angles with respect to this panel 14, as depicted in FIG. 2. Thus the cut 19 stiffens the folding line 17 close to the removals of material 18. It prevents the removal of material 18 from tearing and “propagating” along the folding line when the case 2 is handled.

The entering lug 16 can have rounded edges 21 in order to facilitate its insertion when the closure lug is closed.

Lateral lugs 24 and 25 are adjacent to and articulated respectively on opposite edges situated on each side of the rear panel 6, for example the lateral panels 7 and 9, through folding lines 26 and 27. These lateral lugs extend on the same side as the opening/closing panel 14 and have a substantially trapezoidal shape. The folding lines 26 and 27 form the large bases of the trapezia. Close to the folding lines 26 and 27, the lateral lugs 24 and 25 each comprise a step, respectively 28 and 29. These steps 28, 29, comprising a part of the sheet of flexible material and a part of the sheet of rigid thick material, are themselves rigid and thick. These rigid steps project towards the front panel 5 when the blank 1 is made up. Their function will be described in relation to the description of the case 2.

According to the embodiment depicted in FIGS. 1 and 2, the blank 1 comprises a second closure lug 22 articulated on the rear panel 6 through a folding line 23, on the opposite edge to the folding line 15 of the rear panel 6. Lateral lugs 30 and 31 are provided on the opposite sides to the folding lines 26 and 27 of the lateral panels 7 and 9. Folding lines 32 and 33 separate the lateral lugs 30 and 31 from the lateral panels 7 and 9. These lateral lugs 30 and 31 also comprise rigid steps projecting towards the front panel 5 when the blank 1 is made up.

All the folding lines of the blank 1 are produced by cutting the sheet of rigid material solely and tracing lines on the sheet of flexible material. This type of cut is referred to as a “half-way cut”, only one of the two sheets in the complex being cut.

A method of producing a blank 1 as described above is now described.

The first step of the method consists of producing the complex comprising sheets of flexible thin material, such as cardboard or plastics material, and a sheet of rigid thick material, such as wood or metal or plastic.

The sheet of rigid material and the sheet of flexible material are associated by fixing the sheet of rigid material to one of the faces of the sheet of flexible material. This fixing is for example provided by gluing the sheet of rigid material to the sheet of flexible material.

Next the complex is cut so as to form the lateral panels, the closure lug or lugs, the gluing lug and the lateral lugs.

The sheet of rigid material is cut along the folding lines and the folding lines are traced on the sheet of flexible material. The blank 1 thus has conferred on it the flexibility necessary for its folding and its making up around the folding lines.

The cut 19 can also be made by cutting the sheet of rigid material during this step.

The removals of material 18 are then performed by complete cutting of the complex.

With reference to FIG. 2, a description is now given of the case 2 produced by folding a complex as described above, the said complex having been produced and cut according to the method described above in order to form a blank 1.

The case 2 is therefore produced by making up the blank 1, which is folded along the folding lines. It should be noted that the gluing lug 12 makes it possible to fix the front panel 5 to the lateral panel 7 so as to maintain the volume formed by the folding of the blank 1.

The blank 1 is folded so that the sheet of flexible material forms the internal face 3 of the case and the sheet of rigid material forms its external face 4.

The making up of a blank 1 like the one depicted in FIG. 1 forms a case with a substantially parallelepipedal shape comprising a body 36 formed by the lateral panels 5, 6, 7 and 9, two openings, one of which 34 is visible in FIG. 2, defined by the edges of the lateral panels 5, 6, 7 and 9. According to a particular embodiment, the body of the case can comprise an opening produced by a cutting of the complex.

The lateral lugs 25 and 24 are folded at right angles with respect to the lateral panels 7 and 9, so that they partially cover the opening 34. The rigid steps 28 and 29 of these lugs then project towards the front panel 5 and are situated close to the folding lines 26 and 27.

The folding lug is folded above the opening 34, so that the opening/closing panel covers this opening when it is wished to close the case 2. To this end, the dimensions of the opening/closing panel are adapted to correspond to those of the opening 34. In order to lock the closure lug in the position of closure of the case, the entering lug 16 is folded at right angles with respect to the opening/closing panel 14.

The lug 16 is inserted between the front panel 5 and the lateral lugs 24 and 25. This insertion is facilitated by rounded edges 21 of the entering lug 16. The insertion of the entering lug 16 has the effect of making the rigid steps 28 and 29 enter the removals of material 18. The rigidity and thickness of the sheet of rigid thick material confers on the steps 28, 29 and on the edges of the removals of material 18 sufficient rigidity and thickness to make it possible to obtain a snapping of the rigid steps 28, 29 into the removals of material 18, so that the closure position of the case is firmly maintained and can be defeated only by manual manipulation of the closure lug.

In order to improve the snapping in, the steps 28, 29 can have a generally trapezoidal shape, the small base being produced on the edge close to the front panel 5, and a dimension parallel to the folding lines 27, 26 allowing their insertion in the removals of material 18 without projection.

According to the embodiment depicted in the figures, the second opening is closed in a similar fashion by the second closure lug 22.

The cuts 19 project substantially perpendicular to the opening/closing panel 14 when the entering lug 16 is folded at right angles with respect to this panel 14, so that the folding line 17 is stiffened close to the removals of material 18 in order to prevent any tearing of this folding line 17, which is subjected to stresses when the case 2 is opened or closed. 

1. A case produced by folding a complex, the complex comprising a sheet of flexible thin material with which there is associated a sheet of rigid thick material, the said case comprising: a body (36) comprising lateral panels (5, 6, 7, 9), including at least one front panel (5) and one rear panel (6), at least one first opening (34) defined by the lateral panels, some of the edges of the opening each carrying a lateral lug (24, 25) folded at right angles with respect to a lateral panel of the case along a first folding line (26, 27), the lateral lugs comprising a rigid step (28, 29) close to the first folding line and projecting towards the front panel (5) of the case (2), the case being characterised in that it also comprises at least one lug closing the opening at one of the ends of the body (36), the closure lug comprising an opening/closing panel (14) articulated on the rear panel (6) along a second folding line (15), the opening/closing panel comprising, at its end opposite to the second folding line (15), an entering lug (16) foldable at right angles with respect to the opening/closing panel along a third folding line (17) substantially parallel to the second folding line (15), the third folding line (17) comprising in its end parts a removal of material (18) through each of the sheets in the complex, the rigid steps (28, 29) on the lateral panels being inserted in the removals of material (18) when the closure lug is folded over the opening (34) so as to obtain, because of the rigidity and thickness of the sheet of rigid thick material, a snapping of the rigid steps into the removals of material in order to lock the closure lug in the position of closure of the case (2).
 2. A case according to claim 1, characterised in that the folding lines of the case (2) are produced by cutting the sheet of rigid material of the complex.
 3. A case according to claim 1, characterised in that the third folding line (17) comprises, close to the removals of material (18), a cut (19) made in the sheet of rigid material, the cut being substantially perpendicular to the third folding line (17) and extending partially over the opening/closing panel (14) and over the an entering lug (16), the cut being arranged so that the rigid material forms a projection substantially perpendicular to the opening/closing panel (14) when the entering lug (16) is folded at right angles with respect to the panel, so as to stiffen the third folding line (17) close to the removals of material (18).
 4. A case according to claim 1, characterised in that the lateral lugs (24, 25) have a trapezoidal shape, the first folding line (26, 27) between the said lugs and the lateral panels (7, 9) forming the large base of the trapezium.
 5. A case according to claim 3, characterised in that the entering lug (16) of the closure lug has rounded edges (21).
 6. A case according to claim 1, characterised in that it comprises a second opening opposite to the first opening (34) with respect to the body (36) of the case (2), the second opening being closed by a second closure lug (22).
 7. A case according to claim 1, characterised in that the sheet of rigid material of the complex is situated on the same side as the external face (4) of the case (2), the sheet of flexible material forming the internal face (3) of the case.
 8. A case according to any one of claims 1 to 7, characterised in that the body of the case comprises an opening produced by a cutting of the complex.
 9. A blank intended for producing a case (2), this blank (1) being produced from a complex comprising a sheet of flexible thin material with which there is associated a sheet of rigid thick material, the blank comprising: lateral panels (5, 6, 7, 9), including at least one front panel (5) and one rear panel (6), separated by folding lines and defining the body (36) of the case by folding, lateral lugs (24, 25) adjacent to some of the lateral panels (7, 9) and articulated on these by folding lines (26, 27), a gluing lug (12) adjacent to the front panel (5) and articulated on this by a second folding line (13) substantially parallel to the folding line separating the lateral panels, the blank being characterised in that it also comprises an opening/closing panel (14) adjacent to the rear panel (6) and articulated on the said rear panel by a third folding line (15), the said opening/closing panel comprising, at its end opposite to the third folding line (15), an entering lug (16), the entering lug being articulated on the opening/closing panel (14) by a fourth folding line (17) substantially parallel to the third folding line (15), the fourth folding line (17) comprising, in its end parts, a removal of material (18), the folding lines being produced by cropping the sheet of rigid material in the complex.
 10. A blank according to claim 9, characterised in that the lateral lugs (24, 25) each comprise a rigid step (28, 29) close to the first folding line (26, 27) separating the lugs from the lateral panels (7, 9), the rigid steps projecting towards the front panel (5).
 11. A blank according to claim 9 or 10, characterised in that the fourth folding line (17) comprises, close to the removals of material (18), a cut (19) produced in the sheet of rigid material, the cut being substantially perpendicular to the fourth folding line (17) and extending partially over the opening/closing panel (14) and over the entering lug (16), the cut being arranged so that the rigid material forms a projection substantially perpendicular to the opening/closing panel (14) when the entering lug (16) is folded at right angles with respect to the opening/closing panel (14).
 12. A blank according to claim 9, characterised in that the lateral lugs (24, 25) have a trapezoidal shape, the folding line (26, 27) between the said lugs and the lateral panels forming the large base of the trapezium.
 13. A blank according to claim 9, characterised in that the entering lug (16) of the closure lug has rounded edges (21).
 14. A blank according to claim 9, characterised in that it comprises a second closure lug (22), the second closure lug comprising an opening/closing panel and a second entering lug, the second opening/closing panel being adjacent to the rear panel (6) and being articulated on the opposite edge to the third folding line (15) by a fourth folding line (23).
 15. A blank according to any one of claims 9 to 14, characterised in that at least one lateral panel (5, 6, 7, 9) comprises an opening produced by cutting the complex.
 16. A method of producing a blank according to claim 9, the said method comprising the following steps: producing a complex by associating a sheet of flexible thin material such as cardboard or plastics material and a sheet of rigid thick material such as wood or metal; cropping the complex so as to form the lateral panels (5, 6, 7, 9), the closure lug, the gluing lug (12) and the lateral lugs (24, 25); producing the folding lines by cropping the sheet of rigid material only; producing a cut (19) in the sheet of rigid material close to the removals of material (18), the said cut extending partially over the opening/closing panel (14) and over the entering lug (16); producing removals of material (18) by complete cutting of the complex.
 17. A method according to claim 16, characterised in that the step of producing the complex is performed by gluing the sheet of rigid material to one face of the sheet of flexible material.
 18. The article according to claim 1 or claim 9, wherein the flexible thin material is cardboard.
 19. The article according to claim 1 or claim 9, wherein the flexible thin material is plastic.
 20. The article according to claim 1 or claim 9, wherein the rigid thick material is wood.
 21. The article according to claim 1 or claim 9, wherein the rigid thick material is metal. 